----------------------------------------------------------------------------- -- | -- Module : Data.Prizm.Color.CIE.LAB -- Copyright : (C) 2013 Parnell Springmeyer -- License : BSD3 -- Maintainer : Parnell Springmeyer -- Stability : stable -- -- Transformation functions and convenience functions, some imported -- from the other modules to ease conversion between representations. ---------------------------------------------------------------------------- module Data.Prizm.Color.CIE.LAB ( -- * Transform to -- ** RGB or Hex toRGB , toHex -- ** CIE LCH or XYZ , toLCH , toXYZ -- * Transform from -- ** RGB or Hex , fromRGB , fromHex -- ** CIE XYZ or LCH , fromXYZ , fromLCH ) where import Control.Applicative import Data.Prizm.Color.CIE (refWhite, transformXYZ) import Data.Prizm.Types import {-# SOURCE #-} qualified Data.Prizm.Color.CIE.LCH as LC import qualified Data.Prizm.Color.CIE.XYZ as X import qualified Data.Prizm.Color.SRGB as S ------------------------------------------------------------------------------ -- Transform to ------------------------------------------------------------------------------ -- | Convenience function to convert LAB to RGB. toRGB :: CIELAB Double -> RGB Integer toRGB = X.toRGB . toXYZ -- | Convenience function to convert LAB to HEX. toHex :: CIELAB Double -> Hex toHex = X.toHex . toXYZ -- | Convert a LAB color to the LCH representation. toLCH :: CIELAB Double -> CIELCH Double toLCH (CIELAB l a b) = let h = transformLCH (atan2 b a) c = sqrt ((a^(2 :: Int)) + (b^(2 :: Int))) in CIELCH l c h -- | Convert a LAB color to the XYZ representation. toXYZ :: CIELAB Double -> CIEXYZ Double toXYZ (CIELAB l a b) = let y = (l + 16) / 116 x = a / 500 + y z = y - b / 200 [nx,ny,nz] = getZipList \$ ((*) <\$> ZipList ((transformXYZ) <\$> [x,y,z])) <*> ZipList refWhite in CIEXYZ nx ny nz ------------------------------------------------------------------------------ -- Transform from ------------------------------------------------------------------------------ -- | Convenience function to convert RGB to LAB. fromRGB :: RGB Integer -> CIELAB Double fromRGB = X.toLAB . S.toXYZ -- | Convenience function to convert HEX to LAB. fromHex :: Hex -> CIELAB Double fromHex = X.toLAB . X.fromHex -- | Convert an LCH color to the LAB representation. fromLCH :: CIELCH Double -> CIELAB Double fromLCH = LC.toLAB -- | Convert an XYZ color to LAB. fromXYZ :: CIEXYZ Double -> CIELAB Double fromXYZ = X.toLAB transformLCH :: Double -> Double transformLCH v | v > 0 = (v / pi) * 180 | otherwise = 360 - ((abs v) / pi) * 180